Fans filled the sidwalks as the San Francisco Giants celebrated their World Series Championship with a parade up Market Street in downtown San Francisco, Calif., on Wednesday Oct. 31, 2012.

Photo: Michael Macor, The Chronicle

Fans filled the sidwalks as the San Francisco Giants celebrated...

Image 2 of 4

Fans filled the sidwalks as the San Francisco Giants celebrated their World Series Championship with a parade up Market Street in downtown San Francisco, Calif., on Wednesday Oct. 31, 2012.

Photo: Michael Macor, The Chronicle

Fans filled the sidwalks as the San Francisco Giants celebrated...

Image 3 of 4

Buildings along the street were filled with fans as the San Francisco Giants celebrated their World Series Championship with a parade up Market Street in downtown San Francisco, Calif., on Wednesday Oct. 31, 2012.

Photo: Michael Macor, The Chronicle

Buildings along the street were filled with fans as the San...

Image 4 of 4

Fans filled the sidwalks as the San Francisco Giants celebrated their World Series Championship with a parade up Market Street in downtown San Francisco, Calif., on Wednesday Oct. 31, 2012.

More than 4,100 San Francisco students apparently played hooky to attend the Giants World Series parade and city celebration Wednesday, despite district pleas that they skip the festivities in favor of school.

On average, about 48,900 students attend city public schools each day. On Wednesday, as confetti blew across Market Street, just 44,700 kids made it to class.

While the big loss was arguably a day's worth of reading, writing and arithmetic, the district also took a big hit to the checkbook. Each of those 4,153 students who went to see Buster Posey and Angel Pagan cost the district $38.27 in state funding - or $158,935.

The vast majority of school skippers were from high schools - where about 23 percent of students were absent, compared with about 3.5 percent on a normal day.

About 7 percent of elementary school students and 9 percent of middle-schoolers were not in their seats Wednesday - compared with about 3 percent on any other day.

The day before the parade, Superintendent Richard Carranzasent a letter home urging parents to send their kids to school rather than head to the parade.

"There is a lot to celebrate with the Giants winning the World Series and Halloween," the superintendent wrote. "Each school community will determine what works best for its students and staff to mark this momentous occasion in a safe environment. Every day and every minute of instruction counts, so please make sure your child is in school and ready to learn."

But given the number of "I played hooky to be here" signs carried by children along the parade route Wednesday, times tables didn't stand a chance against ticker tape and Tim Lincecum.

- Jill Tucker

GOP shrinking: If you think times are tough for Republicans in California, try being a member of the GOP in San Francisco.

While the number of registered Republicans in the state dropped under the 30 percent mark in the latest figures released by Secretary of State Debra Bowen, in the city, only a minuscule 8.7 percent of the registered voters admit to being Republicans.

Not surprisingly, that's by far the GOP's worst showing by in the state, with Alameda County's 14.3 percent coming in second. That also helps explain why the city hasn't had a Republican mayor since George Christopher, who left office in January 1964.

The new voting stats uphold San Francisco's - and the Bay Area's - reputation as a Democratic stronghold. The city's 55.7 percent Democratic registration ranks second in the state, behind only Alameda County's 56.4 percent and just ahead of Marin County's 54.4 percent.

But California's fastest-growing group of voters is made up of those who don't identify with either of the two major parties. And while decline-to-state voters are about 21 percent of the state's total, in San Francisco they're 31 percent with a bullet, also a state best.

It could be a busy day at the local polls Tuesday because voter registration has cracked the half-million mark for the first time in San Francisco. The 501,107 registered voters shattered the previous high-water mark of 486,822, set in the November 2004 presidential election.